Grammar: remove the dead CommandNode.hint_mode field

HintMode became per-node (Node::Hinted) in the node-attached refactor;
the per-command hint_mode field was never the mechanism and is now
read by nothing. Removed the field and its 20 `None` initialisers.

src/dsl/grammar/data.rs

@@ -653,42 +653,32 @@ pub static SHOW: CommandNode = CommandNode {
     shape: SHOW_SHAPE,
     ast_builder: build_show,
     help_id: Some("data.show"),
-    usage_ids: &["parse.usage.show_data", "parse.usage.show_table"],
-    hint_mode: None,
-};
+    usage_ids: &["parse.usage.show_data", "parse.usage.show_table"],};
 
 pub static INSERT: CommandNode = CommandNode {
     entry: Word::keyword("insert"),
     shape: INSERT_SHAPE,
     ast_builder: build_insert,
     help_id: Some("data.insert"),
-    usage_ids: &["parse.usage.insert"],
-    hint_mode: None,
-};
+    usage_ids: &["parse.usage.insert"],};
 
 pub static UPDATE: CommandNode = CommandNode {
     entry: Word::keyword("update"),
     shape: UPDATE_SHAPE,
     ast_builder: build_update,
     help_id: Some("data.update"),
-    usage_ids: &["parse.usage.update"],
-    hint_mode: None,
-};
+    usage_ids: &["parse.usage.update"],};
 
 pub static DELETE: CommandNode = CommandNode {
     entry: Word::keyword("delete"),
     shape: DELETE_SHAPE,
     ast_builder: build_delete,
     help_id: Some("data.delete"),
-    usage_ids: &["parse.usage.delete"],
-    hint_mode: None,
-};
+    usage_ids: &["parse.usage.delete"],};
 
 pub static REPLAY: CommandNode = CommandNode {
     entry: Word::keyword("replay"),
     shape: REPLAY_PATH,
     ast_builder: build_replay,
     help_id: Some("data.replay"),
-    usage_ids: &["parse.usage.replay"],
-    hint_mode: None,
-};
+    usage_ids: &["parse.usage.replay"],};